Lumbar Interlaminar Epidural Injections in Central Spinal Stenosis: Preliminary Results of a Randomized, Double-Blind, Active Control Trial

Abstract

Background: Chronic, persistent low back and lower extremity pain is often caused by spinal stenosis. Surgery and other interventions, including epidural injections, have been used to relieve this pain. However, there is little in the medical literature to support interlaminar, or transforaminal epidural injections under fluoroscopy for managing lumbar pain of central spinal stenosis, while the caudal epidural approach has been studied. Study Design: A randomized, double-blind, active control trial. Setting: A private, interventional pain management practice, specialty referral center in the United States. Objective: This study sought to determine if low back and lower extremity pain secondary to lumbar central stenosis can be managed and long-lasting pain relief can be achieved with interlaminar epidural injections of local anesthetic, with or without steroids. Methods: The study comprised 2 groups: one that received local anesthetic only and another received local anesthetic combined with nonparticulate betamethasone. A total of 120 patients were randomized by a computer-generated random allocations sequence to one of the 2 groups. The results of 30 patients in each group were assessed. Outcomes Assessment: Sixty patients were included in this analysis. Outcomes measurements were taken at baseline and at 3, 6, and 12 months post-treatment. Measurements taken were Numeric Rating Scale (NRS), the Oswestry Disability Index 2.0 (ODI), employment status and opioid intake. A decrease in both the NRS and ODI of ≥ 50% was considered significant. Results: Significant pain relief and improvement in ODI scores were seen in both groups at 12 months. Group I’s significant pain relief was 70%; Group II’s was 63%. The significant ODI improvement in Group I was 70%; in Group II it was 60%. Group I patients on average received 3.8 procedures a year; Group II patients received 4.0 procedures a year in successful group. Over 52 weeks in the successful group, total relief for Group I was 40.8 ± 11.7 weeks; for Group II it was 37.1 ± 12.6 weeks. Combined pain relief and functional status improvement were seen in 80% of patients in Group I and 72% in Group II in successful group. Limitations: The lack of a placebo group and preliminary results are limitations. Conclusion: Patients might benefit from receiving lumbar interlaminar injections with or without steroids for lumbar central spinal stenosis. Key words: Chronic low back pain, lower extremity pain, lumbar spinal stenosis, central stenosis, lumbar interlaminar epidural injections, epidural steroids, local anesthetic.